According to the University of Colorado , the pine beetle outbreak that has resulted in a loss of up to 80 to 90 percent of tree canopy along many of the state's watersheds isn't all bad news. The smaller trees that survive the outbreak increase their uptake of nitrate, keeping the pollutant from entering the streams. Here are the details.
* According to the Colorado State University Extension , mountain pine beetles are the most important insect pest in Colorado's pine forest, often killing millions of trees each year during outbreaks.
* Once beetle have infested a tree, nothing can be done to save it, the extension office stated. Within 10 months of a beetle attack, a tree will show yellowish to reddish foliage throughout the entire tree crown.
* The severe pine beetle outbreak in Colorado and Wyoming is part of a larger, unprecedented outbreak that ranges from Mexico to Canada, the university stated.
* A research team from CU-Boulder has released a new study showing that while logging and severe storms cause more nitrates to enter the streams, the beetle kill actually allows smaller trees and sub-canopy vegetation to take up the additional nitrate.
* For the study, researchers measured stream nitrate concentrations at more than 100 sites in western Colorado which had a range of beetle-induced tree damage among lodgepole pines.
* Research showed that the needles of small pines that survived the infestations had higher concentrations of nitrates than healthy trees outside of beetle-kill areas.
* Understory vegetation left is ecologically advantaged by beetle kill in that it no longer has to compete with larger trees for light, water and nutrients, the university stated.
* According to Professor William Lewis, team member and interim director of the school's Cooperative Institute for Research in Environmental Sciences, the beetle-kill conditions are a benchmark for the protection of sub-canopy vegetation to preserve water quality during forest management activities.
* Lewis stated that the U.S. Forest Service's harvesting practices should take in account the importance of surviving smaller trees for water quality.
* According to the university, nitrate pollution is caused by agricultural runoff and permitted discharges of treated waste from municipal water treatment facilities.
* The study was funded by the U.S. Forest Service, U.S. Geological Survey, the National Science Foundation, the National Oceanic and Atmospheric Administration and the National Park Service. Results from the study were published in the Jan. 14 issue of the Proceedings of the National Academy of Science, the university reported.